Cooling device, projector, and cooling method

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No. 2005-294515, filed in the Japanese latent Office on Oct. 7, 2005, the entire disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a cooling device, a projector, and a cooling method.

2. Related Art

In recent years, small-sized cooling devices for cooling heat generating devices or the like to prevent equipment provided with such devices from being heated to high temperatures thereby ensuring preferable operations of the equipment have been used or planed to be used in various applications.

For example, there is proposed a projector provided with a solid-state light source having high response to a signal supplied thereto and superior light controllability. Although such a solid-state light source, which is a heat generator, increases in a light emission amount in proportion to a current supply amount, the amount of heat generated also increases similarly. Therefore, if a large amount of current is supplied, the solid state light source is damaged, or the life of the light source is shortened, by the heat the solid state light source generates. Accordingly, it has been proposed to prevent the damage of the solid-state light source and to prolong the life of the solid-state light source by cooling the solid-state light source with the cooling device described above.

Incidentally, such a cooling device is specifically provided with a cooling fluid for cooling the heat source such as the solid-state light source and cooling fluid cooling means for cooling the cooling fluid heated to a high temperature by absorbing the heat generated by the heat source. And, in such a cooling device, in order to achieve quietness and low power consumption of the device, it is preferable that the cooling fluid cooling means is driven corresponding to the heat generation amount of the heat generator.

For example, JP-A-2005-70514 (hereinafter referred to as a first document) and JP-A-2000-35613 (hereinafter referred to as a second document) disclose a technology of disposing a thermometer adjacent to the heat source (light source) and changing the driving state of the cooling fluid cooling means in accordance with the output of the thermometer. According to this technology, since it can be arranged that the cooling fluid cooling means only cools the cooling fluid aggressively when the heat generating amount of the heat source increases, driving the cooling fluid cooling means unnecessarily can be eliminated. Besides the above, there is a related device disclosed in JP-A-11-337897.

However, there is inevitably caused a time lag between cooling of the cooling fluid by the cooling fluid cooling means and absorption of the heat of the heat source by the cooling fluid thus cooled. In particular, the time lag described above becomes large in the cooling device using liquid as the cooling fluid, such as the cooling device for cooling a solid-state light source provided to a projector.

Therefore, according to the technology disclosed in the first and the second documents, the temperature of the heat generator temporarily increases. Accordingly, in the cooling device in the related art, in consideration of the temporary temperature rise of the heat generator, it was necessary to design the device so that the temperature thereof did not reach, for example, the damaging temperature even when the temperature of the heat generator temporarily rose. Therefore, the advantage obtained by cooling the heat source with the cooling device was problematically reduced.

SUMMARY

An advantage of some aspects of the invention is to prevent the temporary temperature rise of the heat generator in driving the cooling fluid cooling section in accordance with the heat generation amount of the heat generator.

A cooling device according to an aspect of the invention is a cooling device that cools a heat generator generating heat in response to application of a signal based on a predetermined signal via a cooling fluid (cooling medium) including a cooling fluid cooling section that cools the cooling fluid, a control section that controls the cooling fluid cooling section in accordance with a signal based on the predetermined signal, and a signal processing section that supplies the heat generator with the signal based on the predetermined signal relatively late, and supplies the control section with the signal based on the predetermined signal relatively early.

According to the cooling device of the aspect of the invention having the above features, the signal processing section supplies the signal based on the predetermined signal to the heat generator relatively late, and supplies the signal based on the predetermined signal to the control section that controls the cooling fluid cooling section early, in accordance with the signal supplied to the heat generator based on the predetermined signal.

Therefore, the control section can know the heat value to be generated by the heat generator in the future in response to application of the signal based on the predetermined signal, and drive the cooling fluid cooling section accordingly to the future heat value of the heat generator. In other words, it becomes possible to set the temperature of the cooling fluid to a temperature corresponding to the case in which the heat value of heat generator increases prior to the heat value of the heat generator increasing.

Therefore, according to the cooling device of the aspect of the invention, it becomes possible to prevent the temporary temperature rise of the heat generator in the case in which the cooling fluid cooling section is driven in accordance with the value of the heat generated by the heat generator.

Further, in the cooling device according to another aspect of the invention, the configuration can be adopted in which a plurality of heat generators are provided, and at least the cooling fluid, a cooling fluid cooling section, and a control section are provided for every heat generator.

By adopting such a configuration, it becomes possible to cool each of the heat generators in accordance with the heat value of the respective heat generator even if the heat values of the heat generators are different form each other.

Further, in the cooling device according to another aspect of the invention a specific signal detecting section that detects a specific signal different from the signal based on the predetermined signal is provided, and the signal processing section outputs the predetermined signal in real time in response to the specific signal detecting section detecting the specific signal.

According to this aspect of the invention, since the signal to be supplied to the heat generator and based on the predetermined signal is relatively delayed by the signal processing section, the timing when the heat generator is supplied with the signal based on the predetermined signal is delayed compared to the case in which the cooling device is not applied. Therefore, by adopting such a configuration as described above, it becomes possible to supply the heat generator with the signal based on the predetermined signal in real time in, for example, a predetermined situation.

Further, in the cooling device according to another aspect the invention, a configuration in which the cooling fluid is liquid can specifically be adopted.

Further, a configuration in which the cooling fluid cooling section is a cooling fan can specifically be adopted.

Another aspect of the invention is a projector which includes a light source which is a heat generator, and the cooling device according to the above aspect of the invention.

According to the cooling device of the aspect of the invention, it becomes possible to prevent the temporary temperature rise of the heat generator in the case in which the cooling fluid cooling section is driven in accordance with the value of the heat generated by the heat generator. Therefore, according to the projector of this aspect of the invention, it becomes possible to, for example, drive the light source with larger current and to improve the display characteristics.

Further, in the projector according to another aspect of the invention, a configuration can be adopted in which the light control process is preformed using the signal supplied to the control section and based on the predetermined signal.

By adopting such a configuration, it becomes unnecessary to newly generate the signal for light control process even for the projector performing the light control process.

And, a cooling method according to another aspect of the invention is a cooling method of cooling a heat generating body generating heat in response to application of a signal based on a predetermined signal via a cooling fluid including: supplying a signal based on the predetermined signal to a control section that controls a cooling fluid cooling section relatively early, and supplying the signal based on the predetermined signal to the heat generating body relatively late.

According to the cooing method of the aspect of the invention having an above feature, the heat generator is supplied relatively late with the signal based on the predetermined signal, and the control section that controls the cooling fluid cooling section in accordance with the signal (the signal supplied to the heat generator) based on the predetermined signal is supplied relatively early with the signal based on the predetermined signal.

Therefore, the control section can know the heat value to be generated by the heat generator in the future in response to application of the signal based on the predetermined signal, and drive the cooling fluid cooling section according to the future heat value of the heat generator. In other words, it becomes possible to set the temperature of the cooling fluid to a temperature corresponding to the case in which the heat value of heat generator increases prior to the increase in the heat value of the heat generator.

Therefore, according to the cooling method of the aspect of the invention, it becomes possible to prevent the temporary temperature rise of the heat generator in the case in which the cooling fluid cooling section is driven in accordance with the value of the heat generated by the heat generator.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the accompanying drawings, wherein like numbers refer to like elements.

<figref idrefs="DRAWINGS">FIG. 1</figref> is a schematic diagram showing the rough configuration of a cooling device as one embodiment of the invention.

<figref idrefs="DRAWINGS">FIG. 2</figref> is a block diagram showing a functional configuration of a control system of the cooling device as one embodiment of the invention.

<figref idrefs="DRAWINGS">FIG. 3</figref> is an explanatory chart for explaining the operation of the cooling device as one embodiment of the invention.

<figref idrefs="DRAWINGS">FIG. 4</figref> is another explanatory chart for explaining the operation of the cooling device as one embodiment of the invention.

<figref idrefs="DRAWINGS">FIG. 5</figref> is an explanatory diagram of a projector provided with the cooling device as one embodiment of the invention.

<figref idrefs="DRAWINGS">FIG. 6</figref> is a block diagram showing a specific functional configuration of a data delay section.

<figref idrefs="DRAWINGS">FIG. 7</figref> is another block diagram showing a specific functional configuration of a data delay section.

<figref idrefs="DRAWINGS">FIG. 8</figref> is another block diagram showing a specific functional configuration of a data delay section.

<figref idrefs="DRAWINGS">FIG. 9</figref> is a flowchart of a method of cooling a heat generator via a cooling fluid.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, an embodiment of a cooling device, a projector, and a cooling method according to the invention will be explained with reference to the drawings. It should be noted that the scale size of each member is accordingly altered so that the member is shown large enough to be recognized in the drawings below.

<figref idrefs="DRAWINGS">FIG. 1</figref> is a schematic diagram showing a rough configuration of the cooling device S of the present embodiment. Further, <figref idrefs="DRAWINGS">FIG. 2</figref> is a block diagram showing a functional configuration of a control system S of the cooling device of the present embodiment.

The cooling device S of the present embodiment is for cooling a heat generator H via a cooling fluid (cooling medium) X, and as shown in <figref idrefs="DRAWINGS">FIG. 1</figref>, is configured including tubes <b>1</b>, a reservoir <b>2</b>, a pump <b>3</b>, a heat receiving section <b>4</b>, a heat radiating section <b>5</b>, a cooling fluid cooling section <b>6</b>, a motor control section <b>7</b> (control means), a temperature sensor <b>8</b>, and a signal processing section <b>10</b> (signal processing means). It should be noted that a liquid is used as the cooling fluid X of the present embodiment.

The tubes <b>1</b> are for forming a circulating flow channel of the cooling fluid X, and are formed like a circular shape. And, in nodes of the tubes <b>1</b>, there are disposed the reservoir <b>2</b>, the pump <b>3</b>, the heat receiving section <b>4</b>, and the heat radiating section <b>5</b>.

The reservoir <b>2</b> is for temporarily reserving the cooling fluid X, and is provided with a predetermined capacity of space inside thereof. The pump <b>3</b> is for causing flow of the cooling fluid X in the tubes <b>1</b>.

The heat receiving section <b>4</b> is arranged to be in contact with the heat generator, and is made of a material having a high heat transfer coefficient, such as metal. And, the heat of the heat generator H is absorbed by the cooling fluid X in the heat receiving section <b>4</b>, thereby cooling the heat generator H.

The heat radiating section <b>5</b> is for radiating the heat of the cooling fluid X thus heated to a high temperature by absorbing the heat of the heat generator H, and is configured as a radiator in the present embodiment.

The cooling fluid cooling section <b>6</b> is for cooling the cooling fluid X, and is configured with a cooling fan provided with a fan <b>62</b> and a fan-drive motor <b>61</b> in the present embodiment.

The fan-drive motor <b>61</b> is a motor for driving the fan <b>62</b>. The fan-drive motor <b>61</b> rotationally drives the fan <b>62</b> to cause wind, thus the heat of the cooling fluid X is radiated via the heat radiating section <b>5</b>, thereby cooling the cooling fluid X.

The motor control section <b>7</b> is for controlling the cooling fluid cooling section <b>6</b> in accordance with a signal D<b>1</b>, which is a signal supplied to the heat generator H, based on a predetermined signal and specifically controls the fan-drive motor <b>61</b> to control the rotational frequency of the fan <b>62</b>.

The temperature sensor <b>8</b> is disposed adjacent to the heat generator H so as to be able to measure the temperature of the heat generator H, and is connected to the signal processing section <b>10</b>.

The signal processing section <b>10</b> is for supplying the heat generator H with a signal based on a predetermined signal D relatively late, and for supplying the motor control section <b>7</b> with the signal based on the predetermined signal D relatively early.

Specifically, the signal processing section <b>10</b> is configured including a data delay section <b>20</b> and a temperature control section <b>30</b> as shown in <figref idrefs="DRAWINGS">FIG. 2</figref>.

And, the data delay section <b>20</b> delays, for a predetermined period of time, a signal (the predetermined signal D itself in the present embodiment) based only the predetermined signal D supplied from the outside and supplies the heat generator H with the signal thus delayed, and at the same time, supplies the temperature control section <b>30</b> with the predetermined signal D supplied from the outside in real time. Further, the temperature control section <b>30</b> calculates the value of heat (the heat value of the heat generator H in accordance with the predetermined signal D supplied thereto) to be generated in the future by the heat generator <b>1</b>-H based on both the predetermined signal D supplied from the data delay section <b>20</b> and the measurement signal supplied from the temperature sensor <b>8</b> described above, and then supplies the motor control section <b>7</b> with the calculation result as the signal D<b>1</b> based on the predetermined signal D.

As a result, the heat generator <b>14</b> is supplied with the predetermined signal D with delay, and the motor control section <b>7</b> is supplied with the signal D<b>1</b> based on the predetermined signal D in real time. Namely, the signal processing section <b>10</b> supplies the heat generator H with the signal (the predetermined signal D itself in the present embodiment) based on the predetermined signal D relatively late, and supplies the motor control section <b>7</b> with the signal D<b>1</b> based on the predetermined signal D relatively early.

The operation (the cooling method) of the cooling device of the present embodiment configured as described above will now be explained.

Firstly, it is premised that in the cooling device S of the present embodiment, the pump is driven constantly, and the cooling fluid X is circulated in the tubes <b>1</b> at a constant flow rate.

And, the cooling fluid X absorbs the heat from the heat generator <b>111</b> in the heat receiving section <b>4</b> in the process of circulating in the tubes <b>1</b>, and is cooled in the heat radiating section <b>5</b> by radiating the heat absorbed from the heat generator H, and then further circulates to absorb the heat from the heat generator H in the heat receiving section <b>4</b>.

In such continuous flow, when the predetermined signal D is input to the signal processing section <b>10</b> from the outside, the signal processing section <b>10</b> supplies the heat generator with the predetermined signal D with delay, and supplies the motor control section <b>7</b> with the signal D<b>1</b> based on the predetermined signal D in real time. Namely, the signal processing section <b>10</b> supplies the heat generator <b>11</b> with the signal (the predetermined signal D itself in the present embodiment) based on the predetermined signal D relatively late, and supplies the motor control section <b>7</b> with the signal D<b>1</b> based on the predetermined signal D relatively early.

Specifically, the predetermined signal D input to the signal processing section <b>10</b> is supplied to the heat generator H with a predetermined delay, and to the temperature control section <b>30</b> of the signal processing section <b>10</b> in real time by the data delay section <b>20</b> of the signal processing section <b>10</b>. Further, the present temperature status of the heat generator H is input to the temperature control section <b>30</b> via the temperature sensor <b>8</b>. And, the value of the heat (the heat value of the heat generator H in accordance with the predetermined signal D supplied thereto) to be generated in the future by the heat generator H is calculated from both the predetermined signal D supplied to the temperature control section <b>30</b> in real time and measured temperature of the heat generator H, and the motor control section <b>7</b> is supplied with the calculation result as the signal D<b>1</b> based on the predetermined signal D.

As a result, it becomes possible to adjust the temperature of the cooling fluid X to a suitable temperature to the heat value of the heat generator H in the case in which the predetermined signal D is supplied to the heat generator H by the cooling fluid cooling section <b>6</b> prior to the temperature of the heat generator H varying in response to the predetermined signal D supplied to the heat generator H.

For example, (<figref idrefs="DRAWINGS">FIG. 9</figref>, steps S<b>1</b>-S<b>3</b>) in the case in which the heat value P of the heat generator H rises from P<b>1</b> to P<b>2</b> at a time point tp, as shown in <figref idrefs="DRAWINGS">FIG. 3</figref>, in response to application of the predetermined signal D, since the motor control section <b>7</b> is supplied with the signal D<b>1</b> based on the predetermined signal D in advance, the cooling fluid cooling section <b>6</b> starts the driving operation according to the heat value P<b>2</b> of the heat generator H at a time point t<b>1</b> prior to the time point tp as shown in <figref idrefs="DRAWINGS">FIG. 4</figref>. Since there is a time lag between when the cooling fluid X is cooled by the cooling fluid cooling section <b>6</b> and when the cooling fluid X thus cooled reaches the heat receiving section <b>4</b>, as a result, as shown in <figref idrefs="DRAWINGS">FIG. 4</figref>, the cooling fluid X thus cooled reaches the heat receiving section <b>4</b> right before the time point tp to reduce the temperature θ of the heat generator H from a temperature θ<b>1</b> to a temperature θ<b>2</b>. In other words, the temperature of the cooling fluid X should be adjusted to a suitable temperature for the heat value of the heat generator H prior to the case in which the predetermined signal D is applied to the heat generator H. And, since the heat value of the heat generator increases at the time point tp, the temperature θ of the heat generator H rises again towards the temperature θ<b>1</b> after the time point tp.

According to the cooling device S and the cooling method of the present embodiment as described above, the heat generator H is supplied with the signal (the predetermined signal D itself in the present embodiment) based on the predetermined signal relatively late, and the motor control section <b>7</b>, which controls the cooling fluid cooling section <b>6</b> in accordance with the signal D<b>1</b> based on the predetermined signal, is supplied with the signal D<b>1</b> based on the predetermined signal relatively early.

Therefore, the motor control section <b>7</b> can know the heat value to be generated by the heat generator H in the future in response to application of the signal based on the predetermined signal, and drive the cooling fluid cooling section <b>6</b> according to the future heat value of the heat generator. In other words, it becomes possible to set the temperature of the cooling fluid X to a temperature corresponding to the case in which the heat value of heat generator H increases prior to the heat value of the heat generator H increasing.

Therefore, according to the cooling device S and the cooling method of the present embodiment, it becomes possible to prevent the temporary temperature rise in the heat generator H in the case in which the cooling fluid cooling section <b>6</b> is driven in accordance with the heat value of the heat generator H, thus the heat generator can more efficiently be cooled.

A projector provided with a light source as the heat generator H of the above embodiment and the cooling device S of the above embodiment as a cooling device for cooling the light source will now be explained.

<figref idrefs="DRAWINGS">FIG. 5</figref> is an explanatory diagram of the projector <b>500</b>. In the drawing, the reference numerals <b>512</b>, <b>513</b>, and <b>514</b> each denote a light source, the reference numerals <b>522</b>, <b>523</b>, and <b>524</b> each denote a liquid crystal light valve, the reference numeral <b>525</b> denotes a cross dichroic prism, the reference numeral <b>526</b> denotes a projection lens,

The projector <b>500</b> shown in <figref idrefs="DRAWINGS">FIG. 5</figref> is provided with the three light sources <b>512</b>, <b>513</b>, and <b>514</b> each configured as the present embodiment. As the light sources <b>512</b>, <b>513</b>, and <b>514</b>, LEDs (solid-state light sources) respectively emitting red (R), green (G), and blue (B) are adopted. It should be noted that a rod lens or a fly-eye lens could be disposed behind each of the light sources as an even lighting system for making the intensity distribution of light from the light source even.

The light beam from the red light source <b>512</b> is transmitted by an overlapping lens <b>535</b>R, then reflected by a reflecting mirror <b>517</b>, and enters the red light liquid crystal light valve <b>522</b>. Further, the light beam from the green light source <b>513</b> is transmitted by an overlapping lens <b>535</b>G, and enters the green light liquid crystal light valve <b>523</b>.

Further, the light beam from the blue light source <b>5</b><b>14</b> is transmitted by an overlapping lens <b>535</b>B, then reflected by a reflecting mirror <b>516</b>, and enters the blue light liquid crystal light valve <b>524</b>. It should be noted that the light beam from each of the light sources is overlapped in the display area of the liquid crystal light valve so that the liquid crystal light valve is lighted evenly.

Further, in the entrance side and the exit side of each of the liquid crystal light valves, there are respectively disposed polarization plates (not shown). And, only a linearly polarized beam with a predetermined polarizing direction out of each of the light beams from the light sources is transmitted through the entrance side polarization plate, and enters each respective liquid crystal light valves. Further, a polarization converter (not shown) can be provided in a position anterior to the entrance side polarization plate. In this case, it becomes possible to reuse the light beam reflected by the entrance side polarization plate to make the light beam enter the respective one of the liquid crystal light valves, and thus the light efficiency can be enhanced.

The three colored light beams modulated by the respective liquid crystal light valves <b>522</b>, <b>523</b>, and <b>5214</b> then enter the cross dichroic prism <b>525</b>. The prism is formed by bonding four rectangular prisms, and is provided with a dielectric multilayer film for reflecting red light and a dielectric multilayer film for reflecting blue light disposed on the inside surfaces forming a crisscross. The three colored light beams are combined by these dielectric multilayer films to form a light beam for displaying a color image. And, the light beam obtained by combining the three colored light beams is projected on a projection screen <b>527</b> by a projection lens <b>526</b> to display an enlarged image.

And, in the projector <b>500</b> of the present embodiment, the cooling device S of the above embodiment is used for each of the light sources <b>512</b>, <b>513</b>, and <b>514</b>.

As described above, by providing the cooling device S of the above embodiment capable of preventing the temporary temperature rise of the heat generator as the cooling device for cooling each of the light sources <b>512</b>, <b>513</b>, and <b>514</b>, it becomes possible to, for example, drive the light sources <b>512</b>, <b>513</b>, and <b>514</b> with larger current, and thus the display characteristics can be improved.

Further, in the projector <b>500</b> of the present embodiment, the cooling device S of the above embodiment is used for each of the light sources <b>512</b>, <b>513</b>, and <b>514</b>. Namely, a plurality of heat generators is provided, and the cooling device S is provided for every heat generator.

By adopting such a configuration, it becomes possible to cool the light sources <b>512</b>, <b>513</b>, and <b>514</b> in accordance with the respective heat values of the light sources <b>512</b>, <b>513</b>, and <b>514</b> even if the heat values of the light sources <b>512</b>, <b>513</b>, and <b>514</b> are different from each other.

A specific configuration example of the data delay section <b>20</b> of the signal processing section <b>10</b> in the case in which the projector <b>500</b> of the present embodiment is provided with the cooling devices S will now be explained with reference to <figref idrefs="DRAWINGS">FIGS. 6 through 8</figref>.

<figref idrefs="DRAWINGS">FIG. 6</figref> is a block diagram showing a specific functional configuration of the data delay section <b>20</b>. As shown in the drawing, the data delay section <b>20</b> is configured including a writing/reading section <b>21</b>, a memory <b>22</b>, a delay circuit <b>23</b>, and an analyzing section <b>24</b>. And, it is assumed that, in the present embodiment, a video signal D<b>2</b> and a sync signal D<b>3</b> are input to the data delay section <b>20</b> of the signal processing section <b>10</b> as the predetermined signal D described above.

The writing/reading section <b>21</b> is for temporarily storing the video signal D<b>2</b> provided from the outside in the memory <b>22</b> and retrieving the video signal D<b>2</b> temporarily stored in the memory <b>22</b> to output it. The writing/reading section <b>21</b> temporarily stores the video signal D<b>2</b> in the memory <b>22</b> in accordance with the sync signal D<b>3</b> provided form the outside, and retrieves the video signal D<b>2</b> temporarily stored in the memory <b>22</b> in accordance with the sync signal D<b>3</b> supplied from the delay circuit <b>23</b> to output it (<figref idrefs="DRAWINGS">FIG. 9</figref>, step S<b>3</b><i>a</i>).

Further, the delay circuit <b>23</b> is for delaying the sync signal D<b>3</b> supplied from the outside and outputting it. It should be noted that the delay time of the sync signal by the delay circuit <b>23</b> corresponds to the time difference between the output of a light source control signal D<b>4</b> and the output of a cooling control signal D<b>5</b> described later.

The analyzing section <b>24</b> generates the light source control signal D<b>4</b> for controlling the light source and the cooling control signal D<b>5</b> (the signal D<b>1</b> in the above embodiment) for controlling the cooling fluid cooling section <b>6</b> from the video signal by histogram analysis, and outputs them. Here, the analyzing section <b>24</b> outputs the light source control signal D<b>4</b> relatively late, and outputs the cooling control signal D<b>5</b> relatively early. And, the light source control signal D<b>4</b> is input to the light sources <b>512</b>, <b>513</b>, and <b>514</b>, and the cooling control signal D<b>5</b> is input to the cooling fluid cooling section <b>6</b> via the temperature control section <b>30</b> (<figref idrefs="DRAWINGS">FIG. 9</figref>, step S<b>3</b><i>b</i>).

In such a data delay section <b>20</b>, the video signal D<b>2</b> is temporarily stored in the memory <b>22</b>, and then output with time delay corresponding to the time difference between the output of the light source control signal D<b>4</b> and the output of the cooling control signal D<b>5</b>. Therefore, the timing when the video signal D<b>2</b> is input to the liquid crystal light valves <b>522</b>, <b>523</b>, and <b>524</b> becomes concurrent with the timing when the light source control signal D<b>4</b> is input to the light sources <b>512</b>, <b>513</b>, and <b>514</b>.

It should be noted that in the case in which the parameter obtained for generating the light source control signal D<b>4</b> is output as a control level such as the duty ratio of the light source or the voltage level of the light source in the analyzing section <b>24</b>, the light source control signal D<b>4</b> can be used directly as the cooling control signal D<b>5</b>, and further the light control process can be performed using the light source control signal D<b>4</b>. Meanwhile, in the case in which the parameter obtained for generating the light source control signal D<b>4</b> is output as a signal level of an image such as the AP<b>1</b>, or the peak of an image, or a gray scale value (brightness value) obtained from the histogram analysis in the analyzing section <b>24</b>, the light control process and the image processing such as an expansion process associated with the light control process can be performed using the light source control signal D<b>4</b>.

Further, in the case in which the predetermined signal D supplied from the outside includes a specific signal D<b>6</b> such as an emergency signal besides the video signal D<b>2</b> and the sync signal D<b>3</b>, it is possible to adopt a configuration in which a specific signal detecting section <b>25</b> for detecting the specific signal D<b>6</b> is provided, as shown in <figref idrefs="DRAWINGS">FIG. 7</figref>, and the video signal D<b>2</b> and the light source control signal D<b>4</b> are output in real time without any delay if the specific signal D<b>6</b> is detected.

In the case of adopting such a configuration, it becomes possible to display an emergency broadcast image or the like in real time without any delay. It should be noted that even in such a case, it is preferable to control the light sources <b>512</b>, <b>513</b>, and <b>514</b> not to be heated to the damaging temperature. Specifically, if it seems that the temperatures of the light sources <b>512</b>, <b>513</b>, and <b>514</b> are heated to the damaging temperature or higher, it is possible to reduce the light intensities of the light sources <b>512</b>, <b>513</b>, and <b>514</b> to display a darker image.

Further, projectors are usually provided with decoders for decoding an output from a picture reproducer such as a DVD player device. Therefore, if the predetermined signal D supplied thereto is a signal from the picture reproducer <b>600</b>, as shown in <figref idrefs="DRAWINGS">FIG. 8</figref>, it becomes unnecessary to separately provide the writing/reading section <b>21</b> or the memory <b>22</b> by adopting a configuration in which the decoders <b>26</b> and <b>27</b> are included in the configuration elements of the data delay section <b>20</b>, the decoder <b>26</b> for supplying the liquid crystal light valve with the video signal D<b>2</b> is supplied with the sync signal delayed by the delay circuit <b>23</b>, and the decoder <b>27</b> for supplying the analyzing section <b>24</b> with the video signal D<b>2</b> is supplied with the sync signal in real time.

Although the preferred embodiments of the cooling device, the projector, and the cooling method according to the invention are explained above with reference to the accompanying drawings, it is needless to say that the invention is not limited to the above embodiments. The various shapes and combinations of the configuration elements presented in the embodiments described above are provided for exemplification only, and can be modified in various ways within the spirit or the scope of the invention in accordance with design needs and so on.

For example, in the above embodiments the explanations are made citing the light source for the projector as a specific example of the heat generator H. However, the cooling device according to the invention is not limited to those for cooling the light source of the projector, but can be applied to those for cooling the heat generator providing the heat value to be generated in the future by the heat generator can be calculated based oil the predetermined signal supplied to the heat generator.

Further, in the embodiments described above the explanations are made assuming that the cooling fluid cooling section <b>6</b> is composed of the fan-drive motor <b>61</b> and the fan <b>62</b>. However, the invention is not limited to this configuration, but a peltier element can also be used as the cooling fluid cooling section <b>6</b>.

Further, in the above embodiments, the signal processing sections <b>10</b> in the cooling devices S respectively provided to the light sources <b>512</b>, <b>513</b>, and <b>514</b> can be combined into one section.

Further, in the embodiment described above, the explanations are made citing the LED light source as an example of the solid-state light source. However, the invention is not limited to such an example, but the electroluminescence (EL) or the semiconductor laser can also be used as the solid-state light source.

Further, although the liquid crystal light valve is adopted as the light modulation device in the embodiment described above, micro mirror array devices and so on can also be adopted as the light modulation device.

Still further, although in the above embodiments the image is displayed by projecting the image light on the projection screen using the projection lens, the projection mirror can also be used instead of the projection lens.